Daniel R. Headrick is Professor Emeritus of Social Science and History at Roosevelt University and author of numerous books on world history, including Power over Peoples: Technology, Environments, and Western Imperialism, 1400 to the Present, Technology: A World History (OUP, 2009), When Information Came of Age (OUP, 2000), The Tentacles of Progress (OUP, 1988), and The Tools of Empire (OUP, 1981).